From: Jakub Kicinski kuba@kernel.org
commit a8fc8cb5692aebb9c6f7afd4265366d25dcd1d01 upstream.
While looking at a syzbot report I noticed the NAPI only gets disabled before it's deleted. I think that user can detach the queue before destroying the device and the NAPI will never be stopped.
Fixes: 943170998b20 ("tun: enable NAPI for TUN/TAP driver") Acked-by: Petar Penkov ppenkov@aviatrix.com Link: https://lore.kernel.org/r/20220623042105.2274812-1-kuba@kernel.org Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/tun.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
--- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -327,6 +327,12 @@ static void tun_napi_init(struct tun_str } }
+static void tun_napi_enable(struct tun_file *tfile) +{ + if (tfile->napi_enabled) + napi_enable(&tfile->napi); +} + static void tun_napi_disable(struct tun_file *tfile) { if (tfile->napi_enabled) @@ -709,8 +715,10 @@ static void __tun_detach(struct tun_file if (clean) { RCU_INIT_POINTER(tfile->tun, NULL); sock_put(&tfile->sk); - } else + } else { tun_disable_queue(tun, tfile); + tun_napi_disable(tfile); + }
synchronize_net(); tun_flow_delete_by_queue(tun, tun->numqueues + 1); @@ -864,6 +872,7 @@ static int tun_attach(struct tun_struct
if (tfile->detached) { tun_enable_queue(tfile); + tun_napi_enable(tfile); } else { sock_hold(&tfile->sk); tun_napi_init(tun, tfile, napi, napi_frags);